Apparatus for heat treating foods



G. GRINDROD 1,979,685

APPARATUS FOR HEAT TREATING FOODS Nov. 6, 1 934.

Original FiledFeb. 2, 1928 2 Sheets-Sheet l INVENTOR.

BY I M Z/AM/Mx ATTORNEYS Nov. 6, 1934- e. GRINDROD APPARATUS FOR HEATTREATING FOODS 2 Sheets-Sheet 2 Original Filed Feb. 2, 1928 fir. Z

INVENTOR.

BY 2 M M.- M1

ATTORNEYS Patented Nov. 6, 1934 v UNITED STATES PATENT OFFICE APPARATUSFOR HEAT TREATING FOODS;

George Grindrod, Oconomotvoc, Wis., assignor to Grindrod ProcessCorporation, Waukesha, Wis., a corporation of Wisconsin Originalapplication February 2, 1928, Serial no. 251,304. Divided and thisapplication March 21, 1929, Serial No. 348,832. Renewed March 22 Claims.

My invention relates to apparatus for heat' vide meansto facilitatethermal sterilization in which the process can be carried oncontinuously and rapidly with a large total output for a given period oftime as compared with sterilizing processes as heretofore practiced; toprovide suitable l5 apparatus, in .which a. continuously flowing streamof material may be sub-divided and each sub-division heat treated in thesame manner and to exactly thejsame extent as every other sub-division,whereby precise results can be obtained to provide apparatus which maybe interchangeably used for either pre-warming or sterilizing' purposes;to provide for successively subjecting segregated portions of a movingstream of food to permeating jets of steam moving sweepingly through thesegregated portions of the food in a manner to reach all pcrtionsthereof with like effect and to repeat the operation indefinitely as toany desired number of such segregated portions; to provide means wherebythe product so treated may be delivered into containers, the heattreatment being instantly arrested and the temperature of the foodsimultaneously reduced to a point where change in the characteristics orflavor of the food will not ooour; to provide for completing thetreatment as to any given portion of the food with such expedition thatchanges in the character or flavor of the focd will not occur during theheat treatment; andto provide simple and reliable means to facilitatecarrying on the process and insure accurate and uniform results.

In the drawings:-' Figure 1 is an elevational sectional view of apreferred form of apparatus which I have designed for the purposes of myinvention and embodying its mechanical features.

Figure 2 is an end elevation. Figure 3 is a detail view; enlarged,showing a fragment cf the rotary feeder and distributor in its relationto the steam chest from which the distributing steam passages are fed.

Figure isa cross section drawn to line 4-4 of Figure 1. v i Like partsare identified by the same reference characters through the seve alViews.

In a former Patent No.1,714,597, dated May 28, 1929, I have disclosed amethod of sterilizing milk by what may be termed the kettle or batchmethod. By that method, the milk is sterilized by injecting into it frombeneath, quantities of steam in a manner to heat the milk to a tem-,-perature of about two hundred and thirty degrees F., maintain thattemperature from two to three minutes, and then reduce the temperaturealmost instantly to prevent thermochemical change; but the method andapparatus disclosed in said Patent No. 1,714,597, is subject to certaineconomic disadvantages incident to batch processes in general when largequantities of material require to be expeditiously treated and in caseswhere the source of supply is su stantially continuous. Under suchcircumstagces, the batch process involves .loss of time, loss of heatand other disadvantages incident to intermittent operation, whereasunder other conditions the batch process may be preferred.

The apparatus herein disclosed is designed to provide for a continuousprocess for sterilization of liquiforin materials, substantially uniformin I pass a continuously flowing stream of material I through a treatingzone in which the material is subdivided into small portions andsegregated or sufficiently isolated from other portions in the treatingzone to prevent contamination of the more advanced material from theportions of material in the earlier stages of treatment,

each portion in an advanced stage being also isolated and protected fromunsterile material entering the zone by the interposition of mate rialsundergoing treatment in the less advanced stages. My invention alsocontemplates maintenance of balanced pressures upon the various portionsin said zone whereby there will be no tendency to force material fromonesubdivision into another.

During the passage of the material through said treating zone, Iseparately subject each subdivided portion to the action of jets ofsteam which are delivered into the material below the surface thereof,preferably at constantly changing angles and from constantly changingpoints vented between any portions of the liquid sepa-.

of delivery. These jets may be made to sweep through the material fromone side of the general line of travel to the other side and byinjecting the steam at a high pressure at the point of emergence from atravelingnozzle, the jets are caused to move with a sweeping actionacross the particles of material which they contact, and underneath thesurface of the segregated portion. When the material is to besterilized, the steam may thus enter the material at a predeterminedhigh pressure and a correspondingly high sterilizing temperature, and byemploying a series of steam injecting nozzles along the line of traveleach subdivided portion may be subjected successively to such jets ofsteam in successive stages of its advancement whereby each such portionmay be continuously followed by other portions in different stages .ofadvancement with a resultant continuous delivery of the product.

In this manner each of the small subdivided portions may be made equalin quantity to all other subdivided portions and equally subjected tothe action of equal quantities of steam having.

the same pressure and temperature and sweeping in the same mannerthrough each portion of the material whereby the particles of materialwill have substantially uniform'exposure to the par-'- ticles of steamin each of the subdivisions.

In the improved'apparatus milk, or other material to be treated, will befed from a source of supply into a cylinder or cylindrically curvedtrough 10, which is disposed horizontally, or nearly so, and whichcontains a screw conveyor 11 having a helical blade, the outer margin ofwhich substantially fits the concave interior surface of the cylinderor'trough below a horizontal plane through the conveyor axis, and maysubstantially fit the cylinder wall throughout its area as shown in thedrawings. shaft 12, which is provided with an annular series oflongitudinally extending steam passages 13, (Fig. 4). Each'steam passage13 has ports 15 leading respectively through the wall of the shaft tothe spaces between successive turns of the helical blade of the conveyorso that when the cylinder 10 is filled approximately half-full of milkor other material to be treated, steam may be injected into each portionof milk between successive turns of the blade. When the cylinder isfilled to a level at which its'surface is intersected by the drum ofshaft 12, each such portion of the material will be effectuallypartitioned from the other portions and it may therefore be separatelyand independently subjected to the actio of the associated steam jet orjets. 4

In this way the atmosphere abovethe segre-.

gated portions of material is also subdivided into segregated portionsin the same way that the liquid is divided. Thus communication isprerated by two or more turns of the helixof the shaft such 'asmightotherwise occur through the mediumof the atmosphere above the liquid.With successive portions of the advancing stream thus segregated it willbe obvious that the portions nearest to the outlet will be separatedfrom the infeeding material, not only by the mechanical means providedby the conveyor flight but by the following segregated portions ofmaterial undergoingearlier stages of steam treatment. Therefore while ineach successive space the jets of steam will agitate the material, thedesired degree of isolation can nevertheless be maintained in such-amanner as to insure delivery of a sterile This conveyor 11 has a large.

product where sterility is desired and uniformity in the quality of theproduct even in cases where the process is not being employed forsterilizing purposes.

While I have shown and described the trough 10 as a cylinder for thereason that in the specific or preferred embodiment of my invention asillustrated in the drawings, I employ a cylinder, yet it is essentiallya trough, the material to be treated being below the level of the top ofthe drum-like shaft 12 and the upper portion or wall of the chamber 10serving as a cover. The cylindrical form is preferred for the reasonthat, with the liquid at the level of the shaft the steam and entrainedmaterial above each segregated portion is also separated from that abovethe other portions.

If the material were allowed to fill the cylinder or even to fill it toa level above the drum 12, there would remain no partitioning means. Theportions between successive turns of the helical flange or blade 11would then be permitted to fall below the drum, the material would notproperly receive the steam jets below its surface and with the submergedsweeping action that makes the treatment effective to accomplishcomplete sterilization within a very short interval of time and beforethe material undergoes any substantial chemical or flavor change.

Steam is delivered to the passages 13 from a steam chest 20 whichreceives it from a supply pipe 21. The end 22 of the shaft 12 ismachined and fitted to the wall of the chest 20-on the inner side andthe passages 13 are successively brought into registry with a port 23 insaid wall to receive steam from the chest while being carried past thisport by the rotation of the conveyor. The port 23 is located below theshaft axis,.and preferably registers only with the lowermost passage.But its size and the form of the passage opening are 'such that steamwill be supplied to the passage throughout the major portion of theperiod during which the associated ports are moving through thematerialias'itli'e conveyor rotates. But steam will be delivered onlyinto passages which are in a position to deliver steam directly into thematerial through their ports 15. The ports or outlets are, of course,submerged in the material before the steam jets are projected therefromand, therefore, the steam' does not merelyblow against the .surface ofthe material and form cavities therein,

but on the contrary, travels at high velocity through portions of thematerial underneath its surface with resultant violent agitation (asdescribed in my Patent No. 1,714,597). Preferably, each port 15 isprovided with a projecting nozzle 25 to deliver the steam moreeffectively and to a greater depth into the material than would be thecase if mere ports or apertures were used. If this is done,sterilization may, of course, be accelerated by the impactive andsearing effects of the steam.

A positive feed mechanically driven-pump 27 is employed to deliver thematerial into the cylinder 10. This pump is actuated from the crank 28through the link rod 29' and the lever 30. The crank wheel carries asprocket pulley 31 which drives the conveyor through a chain 32. Thepump and its'actuating mechanism are so con structed as to size andspeed of operation that the material will be delivered to the cylinder10 at a rate calculated to maintain the supply in the cylinder at alevel above the bottom of the shaft 12 and below the top thereof,whereby each successive portion or unit of material will be separatelyconveyed by the screw, given separate heat or steam treatment anddischarged through an outlet duct 35 without intermingling with otherportions while in the cylinder. In this manner I divide the-liquid ormaterial being treated in the trough into segregated portions. As thescrew conveyor rotates, each portion moves toward the discharge end andreceives sweeping jets of steam from the nozzles as they successivelycome into action. The transversely swingorder that the steam maycontinuously escape, I

ing movements of the nozzles are across the path along which thematerial travels and all particles of the material -are therefore veryeffectively reached. The nozzles follow the/helical line of the screw intheir arrangement and therefore each successive nozzle operating uponany given portion of the liquid enters it a little farther toward theoutlet than its predecessors, although in the same relative positionwith reference to the center of the body of material, the latter havingcorrespondingly moved toward the outlet. r

The action of the steam upon the material causes a violent ebullition ofthe latter, and in employ an expansion chamber 36, preferably superposedon or above thecylinder 10 and connected at intervals by the verticalpipes 37. Baflies 38 are placed in the expansion chamber, which alsoserves as a separator for any milk (material) that may be carriedfromthe splashing liquid into this chamber 36. The separated material fallsback usually into the next unit. The steam supply to the cylinder 10 isregulated by a valve 40 which is controlled automatically by a heatregulating or pressure bulb 41 in the expansion chamber, this bulb beingconnected y a pipe 42 with a diaphragm chamber 43, the diaphragm ofwhich is connected with the valve stem in a well known manner.

The rate of steam feed and the size and number of the nozzles 25 will beso proportioned to the quantity of material handled and so calculatedwith reference to the temperature of the time, consistent with thoroughsterilization, and

the material will then be instantly cooled by discharging it into acontainer 44 which may be connected with a suitable condenser 45. Thecontainer 44 may have its outlet controlled by a float 46 and floatcontrolled valve 47 so that the material may be delivered into areceiver under vacuum without allowing steam to blow through the outlet.

When the apparatus is used for pre-warming milk or other material, itsoperation will be the same except that steam of a lower temperature maybe used, or the material fed through the apparatus at a more rapid rate.But with steam at 100 pounds pressure and corresponding temperature,only a few seconds will be required to effect a complete sterilization.With steam at the pressure and temperature above mentioned, thirtyseconds should be ample, although the time interval required will alsovary in proportion to the volume of material in each segregatedportion'or unit and the quantity of steam delivered thereto.

In the use of the apparatus herein described,

. the material may be substantially instantaneous.-

1y raised to the desired temperature, maintained at said temperaturemomentarily andthen all thermo-chemical change is arrested by thechilling that results by release of pressure and the resultingvaporization. When sterilizing the material, the temperature should besuch as to accomplish that purpose in the desired degree with suchmomentary exposure, although the time interval may be varied by varyingthe speed at which the conveyor screw is rotated or by varying thetemperature of-the steam.

I claim:

1. Apparatus of the described class comprising the combination of ahorizontally disposed cylinder, a conveyor therein having a helicalflight, the outer margin of which substantially conforms to and fits theportion of the cylinder below the axis of the conveyor, said conveyorhaving a supporting shaft provided with multiple longitudinallyextending passages, the walls of which are ported to allow steamdelivery, means for connecting the passages successively with a sourceof steam supply when in a position to deliver steam into the lower halfportion of the cylinder, and means for operating the conveyor to feedmaterial through the cylinder in subdivided portions separated from eachother by successive portions of the conveyor flight and the conveyorshaft.

2.-Apparatus of the class described, comprising the combination of achamber through which such materials may bepassed, traveling partitionmeans for subdividing such material into measured portions during theirpassage through such chamber while allowing the material to traveltherethrough substantially as a continuously flowing stream, and meansfor independently heat treating each such subdivided portion during itspassage through the chamber, together with means for; regulatingdelivery of the material into said chamber to maintain a predetermineddepth of material in each subdivided portion, and means for regulatingthe rate of flow of such material through the chamber by mechanicallymoving the partitioning members at a predetermined speed.

3. Apparatus of the class described, comprising the combination of aconveyor trough having inlet and outlet ports and a concave bottom, arotary conveyor therein having a drum-like shaft encircled by a helicalconveyor blade, the outer margin of which conforms-in curvature to andsubstantially fits the inner surface of the lower portion of saidtrough, a superposed expansion chamber having communicating drainageconnection with the trough, means for feeding material into the troughin quantities sufiicient to .maintain its upper surface in a planeintersecting said drumlike shaft, and means for separately injecting,

steam into the subdivided bodies of material to heat the same'to thedesired temperature.

4. Apparatus of the class described, comprising the combination of aconveyor trough having inlet and outlet ports and a concave bottom, arotary conveyor therein having a drum-like shaft encircled by a helicalconveyor blade, the outer margin of'which conforms in curvature to andsubstantially flts the inner surface of the lower portion of saidtrough, a superposed expansion chamber having communicating drainageconnection with the trough, and means for feeding material into thetrough in quantities suflicient to maintain its upper surface in a planeintersecting said drum-like shaft, said drum-like shaft being providedwith nozzles having steam supply connections adapted to deliver steamjets intermittently at intervals corresponding substantially with thoseof nozzle penetration of the mate= rial and while the nozzles arerotating with the shaft transversely to the line of travel of thematerial.

5. Apparatus of the class described, comprising the combination of aconveyor trough having an 5 inlet at one end and an outlet at the other,a screw conveyor in said trough, and interconnected means for operatingsaid screw conveyor and delivering material through the inlet of saidtrough at a rate proportionate to the speed of conveyor rotation and ina manner to maintain a depth of material in the trough substantially atthe axis of the conveyor, said apparatus being provided with passagesadapted to deliver steam into portions of the material while separatedfrom each other by the conveyor flight, whereby said portions may beseparately and independently heated while actuated by the conveyor.

6. Apparatus of the class described, comprising the combination of aconveyor cylinder having an inlet at one end and an outlet at the other,a screw conveyor operatively fitted to said cylinder, and interconnectedmeans for.operating said screw conveyor and delivering material throughthe inlet of said cylinder at a rate pro- 26 portionate to the speed ofconveyor rotation and in a'manner to maintain its level substantially atthe axisof the conveyor, said apparatus being provided with passagesadapted to deliver steam into portions of the material separated fromeach- 30 other by the conveyor flight, whereby said portions may beseparately and independently heated while actuated by the conveyor, saidconveyor cylinder having -a superposed expansion chamber provided withmultiple connections with the interior of the conveyor cylinder toseparately receive steam from the subdivided portions of the material.

7. Apparatus of the class described, comprising the combination of aconveyor trough having an inlet at one end and an outlet at the other, ascrew conveyor in said trough, and interconnected means for operatingsaid screw conveyor and delivering material through the inlet of saidtrough at a rate proportionate to the speed of conveyor rotation and ina manner to maintainv its level substantially at the axis of theconveyor, said conveyor being provided with passages adapted to deliversteam into portions of the material separated from each other by theconveyor flight,

whereby said portions may be separately and independently heated whileactuated by, the conveyor, said conveyor trough having a superposedexpansion chamber having multiple connections with the interior of theconveyor trough to'separately receive steam from the subdivided portionsof the material, and said expansion chamber being provided with meansfor regulating the volumeof steam delivered to the conveyor trough in.

accordance with predetermined pressure and temperature conditionstherein desired to bemaintained,

8. Apparatus of the class described comprising the -combination of aconveyor trough having an inlet at one end and an outlet at the beseparately and independentlyheated while arranged in a circular seriesabout the axis of the being provided with nozzles projecting into theactuated by the conveyor, a receiver connected with the outlet of saidtrough and ported in its upper and lower portions, a float operatedvalve controlling delivery through the lower port, and a condenserconnected with the upper port.

9. In an apparatus for heat treating materials capable of being handledin the manner of liquids, the combination of a conveyor having a shaftprovided with longitudinal passages therein shaft, a steam chest at oneend of the shaft having a port in position for successive registry withsaid passages as the shaft is rotated, and .nozzles adapted to deliversteam from each passage at intervals along the length of the shaft.

10. In apparatus for heat treating materials the combination of acylindrically curved trough provided with inlet and outlet ports at itsrespective ends, a conveyor in the trough, means for feeding materialinto the trough through the inlet port, means for actuating the conveyorand regulating the feeding means in a manner to maintain a predetermineddepth of material in the trough while allowing the conveyor flight andshaft to subdivide such material into portions separated from eachother, and means associated with the'conveyor for delivering steam jetsinto such separated portions of material while the jet delivering meansare being carried through the material by the rotation of the conveyor;said jet delivering means being otherwise inoperative for steamdelivery.

11. Apparatus for heat treating a moving stream of material, comprisingthe combination of traveling partitioningdevices for temporarilyllosubdividing portions of the stream and the spaces above them to preventcommingling with, and contamination from, other portions, travelingsteam nozzles adapted to be submerged at their outlets in the subdividedportions, and means for connecting a source of steam supply underpressure tosaid nozzles when so submerged.

12. An'apparatus for heat treating food comprising thecombination of anenclosure, means for moving material progressively along the interior ofthe enclosure in portions segregated as described to prevent transfer ofbacterial infection, said means including a ported rotary member fordelivering transversely sweeping jets of steam into each segregatedportion of material below the upper level thereof.

13; Apparatus for heat treating foods comprising thecombination of achamber through which such materials may be passed, traveling partitionmeans for subdividing such material into segregated measured portions tobe moved in accordance'with the travel of the partition means, and meansfor substantially independently sterilizing each of the subdividedportions during its passage through the chamber. 35

14. Apparatus for heat treating foods including the combination with atrough-like enclosure,

a conveyor therein provided with a helical flight fitting. the lowerportion of the wall of the enclosure and having a hollow shaft provided,with steam jet nozzles between successive turns of the conveyor, meansfor maintaining a supply of food in the enclosure at a level with itssurface in contact with the hollow shaft, said shaft material and meansfor delivering steam into the material through the submerged jetnozzles.

v 15. Apparatus for heat treating foods, a conveyor for advancingmeasured portions of a 0011- tinuous stream of material, an enclosurefor said conveyor co-operative therewith for segregation of the measuredmaterial and means fordelivering jets of steam into each segregatedportion of material underneath the surface thereof while such materialis being advanced by the conveyor, whereby to effect a constant shiftingof the material with reference to the steam jet.

16. In apparatus for heat treating foods, the combination with acylindrical enclosure, of a conveyor having a helical flight fitted tothe wall of the enclosure and a hollow drum provided with equalquantitative portions, means for segregatsteam jet nozzles, means formaintaining the food supply at a level between the upper and lowersurfaces of the drum whereby to segregate the material and theatmosphere above it in one turn of the helix from the material andatmosphere above it in any turn separated from the first-named turn byone or more turns of the helix "and means for injecting steam into thesegregated portions of material through the nozzles submerged therein,said means being adapted to cut oh the supply of steam to theun-submerged nozzles.

1'7. In apparatus for heat treating liquiform foods, the combinationwith a cylindrical conveyoi' chamber, of a helical conveyor foradvancing the food in separated and substantially ing each portion. fromthe other portions and means for injecting steam into the segregatedportions, said conveying means being adapted to cause a relativelytransverse travel of the Jet with reference to the material. I

18.- Apparatus for sterilizing a moving stream of foodmaterial,comprising the combination of partitioning devices adapted totemporarily subdivide and segregate. portions of the stream and meansfor injecting high velocity steam jets into such portions while. movingalong the general line of travel of the stream.

19. In apparatus of the class described, in combination, a container, aconveyor in said container, said conveyor including a shaft havingpassages therein arranged in a circular series about the axis of theshaft, a steam chamber at one end of the shaft, having a port inposition.

for successive registry with said passages as the shaft is rotated,nozzles adapted to deliver high velocity steam jetsfrom' each passage atintervals along the length of the shaft, and said steam jets alwaysbeing directed into the material being treated beneath the liquid levelthereof.

20. In apparatus for treating liquiform material, in combination, acontainer having a receiving portion and a delivery portion, means forfeeding liquiform material to be treated'to said container, meansassociated with said'ccntainer for subdividing the material beingtreated into separated portions, and at the same timecontinuously'moving each portion from the receiving end of saidcontainer to the delivery end thereof, and means for injecting highvelocity steam jets into each portion.

21. In apparatus of the class described, in combination, a container forholding liquiform material to be treated, means for delivering a con-GEORGE 'oamnaon,

